[thirdparty/glibc.git] / sysdeps / powerpc / powerpc32 / power6x / fpu / s_lround.S

/* lround function.  POWER6x, PowerPC32 version.
   Copyright (C) 2006-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>
#include <math_ldbl_opt.h>
#include <libm-alias-float.h>
#include <libm-alias-double.h>

/* long [r3] lround (float x [fp1])
   IEEE 1003.1 lround function.  IEEE specifies "round to the nearest
   integer value, rounding halfway cases away from zero, regardless of
   the current rounding mode."  However PowerPC Architecture defines
   "round to Nearest" as "Choose the best approximation. In case of a
   tie, choose the one that is even (least significant bit o).".
   So we pre-round using the V2.02 Floating Round to Integer Nearest
   instruction before we use the Floating Convert to Integer Word with
   round to zero instruction.  */

	.machine	"power6"
ENTRY (__lround)
	frin	fp2,fp1	/* Pre-round +-0.5.  */
	fctiwz	fp3,fp2	/* Convert To Integer Word lround toward 0.  */
	mftgpr	r3,fp3	/* Transfer fpr3 to r3.  */
	blr
	END (__lround)

libm_alias_double (__lround, lround)

strong_alias (__lround, __lroundf)
libm_alias_float (__lround, lround)
Commit	Line	Data
04067002	1	/* lround function. POWER6x, PowerPC32 version.
04277e02	2	Copyright (C) 2006-2019 Free Software Foundation, Inc.
04067002 UD	3	This file is part of the GNU C Library.
	4
	5	The GNU C Library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
	9
	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Lesser General Public License for more details.
	14
	15	You should have received a copy of the GNU Lesser General Public
59ba27a6 PE	16	License along with the GNU C Library; if not, see
59ba27a6 PE	17	<http://www.gnu.org/licenses/>. */
04067002 UD	18
	19	#include <sysdep.h>
	20	#include <math_ldbl_opt.h>
216933b2	21	#include <libm-alias-float.h>
d17542d2	22	#include <libm-alias-double.h>
9c84384c	23
04067002	24	/* long [r3] lround (float x [fp1])
9c84384c	25	IEEE 1003.1 lround function. IEEE specifies "round to the nearest
04067002 UD	26	integer value, rounding halfway cases away from zero, regardless of
04067002 UD	27	the current rounding mode." However PowerPC Architecture defines
9c84384c JM	28	"round to Nearest" as "Choose the best approximation. In case of a
9c84384c JM	29	tie, choose the one that is even (least significant bit o).".
04067002 UD	30	So we pre-round using the V2.02 Floating Round to Integer Nearest
	31	instruction before we use the Floating Convert to Integer Word with
	32	round to zero instruction. */
	33
	34	.machine "power6"
	35	ENTRY (__lround)
	36	frin fp2,fp1 /* Pre-round +-0.5. */
	37	fctiwz fp3,fp2 /* Convert To Integer Word lround toward 0. */
	38	mftgpr r3,fp3 /* Transfer fpr3 to r3. */
	39	blr
	40	END (__lround)
	41
d17542d2	42	libm_alias_double (__lround, lround)
04067002 UD	43
04067002 UD	44	strong_alias (__lround, __lroundf)
216933b2	45	libm_alias_float (__lround, lround)